The keirin, which means "war on wheels" in Japanese, is now a high profile Olympic sport and attracts millions of spectators. It is primed to be one of the must-see events of the 2021 Tokyo Olympics. But its origins are humble, even strange. Like the Tour de France was originally conceived to sell newspapers, the keirin was invented in post-war Japan as a way to raise taxes on gambling. Now, more than $12 billion a year is wagered on it, and its stars are primed to make millions. Unlike a traditional race, a pacemaker leads eight riders up to speeds of 50mph on huge concrete velodromes. Then, they break away and fight to cross the line first, with riders pushing, shoving, and crashing in the final dramatic stretch. Long associated with the working class, even the notorious yakuza crime syndicates, riders today live in blacked-out dorms, with no access to technology, in order to prevent bet-rigging. These athlete’s lives are ruled by ritual and competition, from their rookie days at the Mt. Fuji training camp to elite competitions that are the Japanese equivalent of the Grand National. Foreign riders sometimes compete, but rarely prosper in this intense environment, and the Olympic version is a mere child's play to the fierce environs of the velodromes in Tokyo and Osaka, where a specter of danger still looms. Vivid and completely absorbing, explores a side of Japan we rarely see and reveals its uniquely fascinating sporting culture.